One of the best scenes is the slow-motion wordless scene where the pack, with Xander as a leader, is walking through the schoolyard, and everyone is looking at them. The music in that scene ("Job's Eyes" by Far) is perfect, it really creates the feeling of danger and dread. I think this is the first time a song by a band is simply used as musical background in a scene without it being played in-universe (usually it's a band playing at the Bronze or someone playing a song), which is a bit more unusual for the show but does happen occasionally.
Another strong scene is the one in the gym when the game of dodgeball turns ugly and the pack starts ganging up on the nerdy Kyle, their earlier victim/target. I didn't find it unrealistic at all that the coach didn't do anything - from my high school experience, it's very common to see teachers not lift a finger to stop obvious bullying between students. The coach in this scene is not the same guy we'll later see in Go Fish, but they have the same mentality - instead of being shocked, this guy is also impressed with the hyena-students' brutality to other students (“God, this game is brutal. I love it!”). The show portrays school coaches in a very dark way (we'll get to see more on the subject in Nightmares and Go Fish, the latter is built on the idea that athletes are encouraged or made to be inhuman so they could perform better). One might compare hyena possession to the effect of steroids. The hyena-possessed students not only have more confidence and aggression, they also seem to have enhanced senses (Xander's super-hearing) and physical strength (Giles says that they can individually match Buffy), similar to supernatural beings such as vampires whose strength come from demonic sources.
The unfortunate pig Herbert the mascot served well as a red herring - from the moment he was introduced it was easy to guess he would get eaten by the pack, but I don't think many people would have guessed that Principal Flutie will meet the same fate. That was a real surprise the first time I watched the show. Flutie was a good character and quite funny, more so than I remembered. But I think Snyder was even funnier and a really great and enjoyable 'love to hate' character. He was much worse for the students, but even more fun for the show.
Nick Brendon is excellent playing a much darker, meaner version of Xander. Although Xander is not himself, it is not a simple possession, in which a person's body is under control from another being (say, Cordelia/Jasmine); but rather, it seems that the influence of the hyena spirit is drawing out Xander's suppressed aggression and making him act on his darker urges (including acting on his attraction for Buffy by trying to rape her), and in the end, regular Xander still remembers everything, even though he pretends not to in front of Buffy and Willow to make things easier for himself. I was struck by how much Hyena!Xander's behavior with Buffy and Willow was similar to the behavior of soulless vampires in later seasons. Xander insulting Willow in a particularly cruel way and enjoying her pain reminded me of Angelus and his emotional torment of Buffy in season 2, as well as some of Spike's gratuitous insults to Buffy in season 4 and 5. Xander might not see Willow in a romantic/sexual way at this point, but maybe, besides just talking pleasure in being cruel, he's trying to distance himself from a girl he has tender and very human feelings for. The way Xander acts around Buffy is a lot like season 5/6 Spike at his most sexually aggressive (calling Buffy "Slayer", telling her that she likes men being dangerous and mean, saying things like "When are you going to stop pretending we're not attracted to each other"...). Hyena!Xander can also be deceptive and manipulative - he's very good at pretending to be regular Xander (a bit like Angelus pretending to be Angel in season 4 of AtS) so much that he almost fooled Willow. Almost, since Willow shows that she's a tougher cookie and not so easily duped, not even by someone she cares about so much.
This is the first time in the series that Buffy gets sexually assaulted (and the second episode that features a sexual assault - Xander was one of the victims in "Teacher's Pet" and is the perpetrator in his second centric episode) and while she's shocked, she keeps her cool and is relatively undisturbed by the experience after fighting him off. It's interesting to compare her reaction to her much more vulnerable behavior in season 6. But there are plenty of differences in circumstances that can explain that - in "The Pack", although it's also by someone she's close to, she knows that Xander is not being his normal self, and also she hasn't had an intimate relationship with him with a lot of messy and complicated feelings involved.
Shippy developments: At the beginning of the episode, Willow and Buffy have another talk about boys, and we get an explicit confirmation of Willow's crush on Xander. Buffy says that she remembers the feeling (who is she referring to - Pike? Ford? Maybe Jeffrey?), but hasn't felt it for a long time (what about Owen? Has he been forgotten already, or does she just mean that the attraction wasn't that strong?) before admitting that she's attracted to Angel, but doesn't see a relationship with him because he's rarely around and just talks about Slaying. I can see why Willow calls Angel "mysterious older man", but why does Hyena!Xander call him "dangerous and mean", when he still had no idea that Angel was a vampire or had a dark past? Did he just assume that because of the mystery and the leather jacket, or maybe the animal spirit allowed Xander to instinctively feel the demon in Angel? Hyena!Xander also seems aware of Willow's feelings for him, but regular Xander seems clueless (as we later see in "Prophecy Girl") - maybe he is aware of it on a subconscious level but doesn't want to think about it?
The climax with the parallel scenes of Xander assaulting Buffy and the other four pack members killing and eaten Principal Flutie was well done, but it's a bit of a cop-out that he wasn't with them. It would be harder to have an upbeat ending if one of your main characters had committed murder and cannibalism, even if he wasn't really responsible for his actions. I was thinking of giving this episode a 4, but the ending took half a point from it. An attempted rape is a serious matter, and even if Buffy and Willow are acting like everything is OK now that Xander is back to normal, the fact that Xander remembers everything means that he should feel disturbed by the things he did in his hyena state, maybe even look for some counseling. Instead, Giles smiles promising to keep his secret, and everything is soon forgotten. Not to mention those other 4 kids who killed and ate the principal and presumably also remember it; they aren't facing any punishment since the act is officially attributed to wild dogs, but how are they coping with it? They may have been jerks and bullies before, but murder and cannibalism is something else. This is a typical problem of season 1, lack of follow-up and upbeat endings even when they're not quite appropriate.
Giles: Xander's taken to teasing the less fortunate?
Giles: And, there's been a noticeable change in both clothing and demeanor?
Giles: And, well, otherwise all his spare time is spent lounging about with imbeciles.
Buffy: It's bad, isn't it.
Giles: It's devastating. He's turned into a sixteen-year-old boy. Course, you'll have to kill him.
Giles: Testosterone is a great equalizer. It turns all men into morons.
- Yes, it's similar to the best lines above, but those were funny. Didn't Giles notice that two out of five pack members were girls?
Pop culture references: The X-Files (Buffy to Giles: “I can’t believe that you, of all people, are trying to Scully me!” I love that line.)
Denial Buffy: about Angel: "Some girls might find him attractive..." This time, however, she quickly realizes she's not fooling Willow and adds "... OK - if they have eyes."
Character death: Principal Flutie - in an episode in which he was more likable than usually.
Main character goes evil: 1
Foreshadowing: Willow tells Xander that he would end up in a poor job as the guy working in the pizza place – which is similar to where Xander will be at the start of season 4.